The present invention relates generally to a character reading apparatus and more specifically to an apparatus for reading a series of preprinted magnetic characters on a bank check while the check is being automatically moved through the apparatus.
To improve the efficiency of check processing, bank checks have been standardized to include a set of magnetic characters preprinted in a certain way in predetermined areas on the checks. These magnetic characters include bank numbers, account numbers, and other specific alphanumeric and symbolic information. FIG. 1 illustrates a standard bank check .generally designated by reference numeral 10. Check 10 includes a specific area which is made up of a certain number of cells 12, each of which is a standard size. The United States banking system has developed what is referred to as the E13B standard which defines a standardized set of magnetic characters preprinted in specific locations within the, se cells. FIG. 2 illustrates two of the characters within this set of characters, the zero and the one, and shows their proper location within their cells.
Referring to FIG. 2, each cell 12 is divided into ten equal width zones 14. Each of the characters making up the standard character set is specifically defined by positioning magnetic printing within certain portions of certain zones 14 of a given cell 12.
The above described character set was developed to allow automated reading of the characters using a magnetic read head. FIGS. 3A-N are graphs illustrating the expected analog electrical signal waveform generated by each of the magnetic characters making up the standard character set when the characters are moved past a magnetic read head in a specific way, that is, at a specific orientation with respect to the read head and at a specific constant speed. For purposes of convenience, the various waveforms are designated by the reference numerals 15A-N.
In order to accurately identify a character, you must first accurately generate its unique waveform. This requires not only moving the characters past a read head to generate a waveform but also requires determining which specific portions of the resulting waveform correspond to each portion of each character. Two prior art general approaches have been used to provide a device which is intended to read the above described standard magnetic character sets.
The first approach attempts to hold the velocity of the check constant as the check moves past the read head and synchronizes its recognition circuitry with the known velocity. As the waveform is generated the known velocity is used to divide the waveform into sections which correspond to each character. These character waveforms characteristics am then compared with stored, expected waveform characteristics to identify each character. If for some reason the velocity has varied, the waveforms characteristics may not match any of the expected waveforms characteristics and a particular character may not be recognized, or may be recognized incorrectly, which is even worse than not recognizing it at all. To minimize this problem, typically a flywheel or other high inertial system is used to obtain constant velocity, While this may be satisfactory for some applications, it requires larger more expensive drive motors, gears, or other components which increase the costs. Also the electrical requirements are typically larger and the device requires a more expensive regulated power supply.
In the second approach, the displacement of the check relative to time is monitored as the check moves past the read head. Therefore this approach is not concerned with variations in the speed of the check, at least to a limited extent. The information provided by monitoring the movement of the check is used to adjust the information provided by the electrical signal waveform from the read head. This combination of information is then used to match the expected signal that would be generated if the speed had been a specific constant speed. A character recognition device of this type must include an arrangement for measuring the displacement of the check and an arrangement for storing and using this information to modify the information provided by the read head. These additional components which make up the above described arrangements again add to the expense of the device. Also, the additional requirement: of modifying the information from the read head requires a more powerful processing device adding still more to the costs and increasing the required processing time.
Both of the above described approaches to providing a character recognition device require some method of storing and processing the information defining the expected waveform for each of the characters in the character set. Typically this is done by storing a complete analog or digital representation of the expected analog waveform. This approach requires a relatively large amount of memory space and a more powerful processor to handle this volume of information, again adding to the expense of the device.